Finding the Fourth Proportional to 8,085.79, 11,152.37 and 7,139.91

Step by Step Solution

1. Step 1: Write the proportion equation
   8,085.79 : 11,152.37 = 7,139.91 : x
2. Step 2: Convert to fraction form
   8,085.79/11,152.37 = 7,139.91/x
3. Step 3: Cross multiply
   8,085.79x = 11,152.37 × 7,139.91
4. Step 4: Simplify right side
   8,085.79x = 79,626,935.94
5. Step 5: Solve for x
   x = 79,626,935.94/8,085.79
6. Step 6: Final answer
   x = 9,847.77